How to use assert() macro in C

Macro assert()

• • The purpose

More reliable program. For debugging

• • Definition

#include <assert.h>

void assert (scalar expression);

• • Description

If expression which shall have a scalar type is false ( = 0), The eassert() macro will wirte information about the particular call that failed on stderr and call abort().

That information include:

• • The text of argument

  • The name of the source file

  • The source file line number

  • The name of the enclosing function: the latter are, respectively, the values of the preprocessing macros __FILE__ and __LINE__ and of the identifier __func__.

No return value

No errors are defined

How to use

• • Expression should be true

  • Example

assert_test.c

/*

* =====================================================================================

*

* Filename: assert_test.c

*

* Description: Test macro assert()

*

* Version: 1.0

* Created: 01/22/2013 09:58:30 AM

* Revision: none

* Compiler: gcc

*

* Author: quyendv

* Company: dovanquyen.vn@gmail.com

*

* =====================================================================================

*/

#include <stdio.h>

#include <assert.h>

int main()

{

int x = 0;

printf("Enter a positive integer number x = ");

scanf("%d", &x);

assert(x >= 0);

printf("You have just entered x = %d", x);

return 0;

}

Result:

References

http://pubs.opengroup.org/onlinepubs/009695399/